package/libblockdev: bump to version 3.4.0
Release notes:
https://github.com/storaged-project/libblockdev/blob/3.4.0/NEWS.rst
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
[Julien: remove "security" in commit log title]
Signed-off-by: Julien Olivain <ju.o@free.fr>